Almost without exception, published drill results include highlights – smaller intervals of higher grade results within a larger drill core. The problem with this approach is that the highlight skews our average grade up significantly for the full drill interval. Depending on the project geology this isn’t always a problem, but it can be misleading (also known as “grade smearing”). We talk about this in more detail in the article “Lies, Damn Lies and Drill Highlights: A Critical Look at Interpreting Drill Results“. This tool allows you to quickly calculate the residual grade for the reported drill interval by excluding the averaging effect of the drill highlight.
A negative result may mean that the reported intervals are incorrect. It may also indicate that the residual grade is zero.
